Continuous negative pressure chamber for infants

ABSTRACT

A continuous negative pressure chamber for treating infants having Idiopathic Respiratory Distress Syndrome including an enclosure with two of the opposed walls of the enclosure each having an opening aligned with each other and each mounting an adjustable iris diaphragm for adjustably engaging the neck and pelvic area of an infant placed in the chamber. A pressure manometer as well as a pressure relief valve are mounted to the chamber. The chamber has a vacuum inlet to which a vacuum source means is connected for producing a continuous negative pressure in the chamber.

United States Patent 191 Bancalari CONTINUOUS NEGATIVE PRESSURE CHAMBERFOR INFANTS [75] inventor: Eduardo H. Bancalari, Miami, Flav [73]Assignee: University of Miami, Coral Gables.

Fla.

[22] Filed: Jan. 21,1974

[211 App]. No.: 435,263

[52] U.S. Cl. 128/1 B; 128/204; 128/1458 [51] Int. Cl. A61M 16/00; A6lHill/00 [58] Field of Search 128/1 B, 298, 30, 30.2,

[56] References Cited UNITED STATES PATENTS 2.3 l4.955 3/1943 Slater128/30 2,572,787 10/195] Wallin 4 r 4 l r l w r r 128/30 Huxley .r128/30 Sept. 9, 1975 Primary Examiner-Richard A. Gaudet Assismrz!ExaminerHenry J. Recla Airumey, Agent, or FirmCushman, Darby & Cushman[57] ABSTRACT A continuous negative pressure chamber for treatinginfants having Idiopathic Respiratory Distress Syndrome including anenclosure with two of the opposed walls of the enclosure each having anopening aligned with each other and each mounting an adjustable irisdiaphragm for adjustably engaging the neck and pelvic area of an infantplaced in the chamber. A pressure manometer as well as a pressure reliefvalve are mounted to the chamber. The chamber has a vacuum inlet towhich a vacuum source means is connected for producing a continuousnegative pressure in the chamber.

6 Claims, 4 Drawing Figures CONTINUOUS NEGATIVE PRESSURE CHAMBER FORINFANTS BACKGROUND OF THE INVENTION This invention pertains to acontinuous negative pressure chamber and in particular to such apparatusfor treating infants having Idiopathic Respiratory Distress Syndrome.

Thousands of new born infants die each year with the IdiopathicRespiratory Distress Syndrome. This condition usually affects prematureinfants which are born before their lungs are fully developed. In suchinfants the alveolar walls are not fully developed and the surfacetension of the material on the walls is too high, causing the lungs ofthe infants to collapse.

Various techniques have been utilized to treat this condition in theprior art. These prior art techniques include, for example, the use ofpositive pressure ad ministered to the infant to expand the lungs withthe positive pressure being administered through an endotracheal tube orsealed head chamber. Recently, a new successful treatment in new bornswith this disease is the use of a continuous negative pressure aroundthe body except the head, in order to expand their lungs. Theeffectiveness of treatment utilizing either positive pressure ornegative pressure is usually expressed as the partial pressure ofarterial oxygen in the blood, conventionally expressed as PaO Whilethere are no proven differences between constant positive and constantnegative pressure, either in relative increase of PaO or in possiblecirculatory changes, continuous negative pressure has the advantagesthat it avoids the use of an endotracheal tube or a tight face mask.

The experiments that have been tried in the prior art with applicationof continuous negative pressure have involved modifications toconventional intermittent negative pressure respirators. These negativepressure respirators are conventional devices which are quitecomplicated and expensive and which vary the pressure over the thoraxarea of a patient from atmospheric pressure to a slightly negativepressure. An example of one such respirator is that disclosed in US.Pat. No. 2,3 l4,955 to Slater. Modification of these conventionalrespirators to provide continuous negative pressure involve, of course,changing them over from intermittent negative pressure operation tocontinuous negative pressure operation. Use of these modifiedrespirators entails enclosing all of the infant's body except its headin the respirator. This has the drawbacks of restricting access to theinfant and entailing loss of negative pressure every time the patientneeds cleaning or care. There is the further difficulty of transferringthe patient in and out of the unit which may compromise the wellbeing ofa very sick infant.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of this inventionto provide a continuous negative pressure chamber for treating infantshaving Idiopathic Respiratory Distress Syndrome.

It is a more specific object of this invention to provide a negativepressure chamber for enclosing only the thorax area and upper abdomen ofan infant for applying a negative pressure to expand the infants lungs.

It is another object of this invention to provide a continuous negativepressure chamber enclosing the thorax area and upper abdomen of aninfant of simple design and construction and of a size such that it maybe placed together with the infant within the confines of a conventionalincubator chamber.

Briefly, in accordance with one embodiment of the invention there isprovided a continuous negative pressure chamber comprising an enclosurewith two opposite walls of the enclosure being spaced apart from eachother a distance corresponding approximately to the distance between aninfants neck and pelvic area with the opposed walls having openingstherein. An adjustable iris diaphragm is provided in each of the opposedwalls for adjustably engaging the neck and pelvic area of an infantplaced in the chamber. A pressure manometer is mounted to the chamberfor providing an indication of the air pressure therein and a pressurerelief valve is mounted to the chamber for relieving the pressure in thechamber if the pressure exceeds a predeter mined limit. The chamberincludes a vacuum inlet and a vacuum source means is provided which isconnected to the inlet for producing a continuous negative pressure inthe chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration ofacontinuous negative pressure chamber in accordance with the inventionshowing an infant placed therein and illustrating the infant with thenegative pressure chamber enclos ing the thorax and upper abdomen of theinfant placed within a conventional incubator chamber.

FIG. 2 is a side view of the adjustable iris closures provided foradjustably engaging the neck and pelvic area of the infant.

FIG. 3 is a schematic illustration of the flexible cylindrical sheetmaterial used to form the iris of FIG. 2.

FIG. 4 is a schematic illustration showing the controls connected to thevacuum inlet of the chamber in accordance with another embodiment of theinvention for cyclically varying the magnitude of continuous negativepressure maintained in the chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIG. I, there isshown in diagrammatic form one embodiment of the invention. A chamher orenclosure 11 is provided which has opposed top and bottom walls andopposed side walls. The chamber 1 1 also has a front 12 and a back 13,each of which has a central opening therein. The openings are alignedwith each other along the axis of the enclosure II and are fitted withadjustable iris diaphragms 14 and 16. The adjustable iris diaphragms l4and 16 can be of the type described in US. Pat. No. 2,695,605, or of anyother suitable construction for adjustably engaging a portion of aninfants body to seal the enclosure 11 to the infants body. In accordancewith the particular embodiment of the invention illustrated in FIG. I,the diaphragms l4 and 16 are of identical construction so that onlydiaphragm 14 will be particularly described. The diaphragm 14 includes astationary frame structure 17 supported in the front 12 of enclosure 11by means of inside flange 17a and a exterior ring 18 which may be madeof an elastic material such as rubber. A closure material 19 is provided(more particularly shown in FIG. 3) which is tubular-shaped flexiblesheet material having elastic rings 19a and I9b disposed at either end.The frame structure 17 has an annular rim 17b to which one end of theclosure I9 is held by one of the elastic rings. The closure material 19is then folded back upon itself and its other end secured by means ofthe other elastic ring to an outer collar 21. The closure material 19thus forms an iris diaphragm which is adjustable by rotation of thecollar 21 with respect to the stationary frame structure 17.

In accordance with the embodiment of the invention shown in FIG. 1, amanometer 22 is provided attached. for example, to one of the side wallsof the enclosure or chamber 11 and functioning to provide an indicationof the pressure of the air within the enclosure II. A pressure relief orpop-off valve 23 is also provided mounted, for example, in the side wallof the enclosure 11 and functioning to relieve the pressure in theenclosure if the pressure exceeds a predetermined limit.

The enclosure 11 has a vacuum inlet 24 connected by means such as tubing26 to a high flow vacuum source which is illustrated in FIG. 1 as a pump27. A baffle 28 is provided within the enclosure ll adjacent the vacuuminlet 24 to prevent materials which might be pres ent in the enclosure11, such as diapers in the bottom of the enclosure for example, fromoccluding the vacuum inlet 24.

In the arrangement illustrated in FIG. 1 the side walls of the enclosure1 I have projecting tabs 29 which mount rod members 31 and 32. The rodmembers 31 and 32 both project past the front and back walls of theenclosure 1]. Flexible material such as tape, cloth, or diapers, forexample, may be wrapped around the projecting portions of the rods 31and 32 to form ham mock-like supports 33 and 34 as illustrated in FIGvI.

To place an infant having Idiopathic Respiratory Dis tress Syndrome intothe chamber or enclosure II, the adjustable iris diaphragms l4 and 16are adjusted to their maximum open position and an infant is insertedlengthwise through the iris diaphragms to the position illustrated inFIG. 1 by the infant 10. The front and back walls 12 and 13 of theenclosure 11 are spaced with respect to each other a predetermineddistance such that the iris diaphragm I4 is adjacent the infants neckand the iris diaphragm 16 is adjacent the pelvic area of the infant. Inpractice, the front and back walls 13 and 12 of the enclosure 11 arespaced with respect to each other a distance of approximately 15centimeters. With the infant 10 in position the iris diaphragms l4 and16 are adjusted by rotating the rotatable collars thereof such as collar21 of diaphragm 14 so as to close the iris of closure material 19 aboutthe neck and pelvic area of the infant. With the dimensions andarrangement of the enclosure 11 as illustrated and described withreference to FIG. I, the negative pressure chamber or enclosure 11encloses only the thorax and upper abdomen of the infant. The infantshead is free as is its pelvic area so that the infant may be cleaned ornursing care administered to the infant without removing it from thechamber 11 thus preventing an interruption of the negative pressurewithin the chamber 11. Thus an oxygen mask 36 may be applied to theinfant if necessary. The leads of monitoring equipment and an umbilicalarterial catheter may be passed through one of the irises, such as irisdiaphragm I6 for example.

The enclosure or chamber 11 can be made of any suitable material but ispreferably made of a transparent material such as plexiglass so that theenclosed thorax and upper abdomen of the infant may be visuallyobserved. Also, with an enclosure ll made of plexiglass, X-rays may betaken of the infant while its thorax is enclosed in the chamber 11.

In operation. the pump 27 is utilized to establish a negative pressurewith reference to atmospheric pres sure within the chamber or enclosureII on the order of between 4 and 15 centimeters of H 0. The amount ofnegative pressure required as well as the length of time an infant needsto have the negative pressure applied to its thorax depends upon theseverity of the Idiopathic Respiratory Distress Syndrome with which theinfant is afflicted and can be monitored by monitoring the partialpressure oxygen tension (PaO- in the infants blood. The entire negativepressure chamber or enclosure 11 in accordance with the invention issuitably dimensioned so that it may be placed within a standardincubator unit 37. Normally, the negative pressure chamber in accordancewith this invention should always be utilized within an incubatorinasmuch as the flow of air around the infants thorax and the air leaksthrough the irises l4 and 16 produce a cooling effect which would bedeleterious to an infant if not utilized within an incubator in whichthe air was heated. Alter natively, instead of being utilized within anincubator the negative pressure chamber in accordance with thisinvention may be placed under an array of infrared lights or otherheat-producing elements.

Turning now to a consideration of FIG. 4 there is shown in diagrammaticform a portion of the vacuum supply means to a negative pressure chamberin accordance with another embodiment of the invention. Infants havingthe Idiopathic Respiratory Distress Syndrome are subject to what isdescribed as apnea, in which the infant just suddenly stops breathing.Usually all that is required to get an infant out of an apnic spell isto physically jolt the infant or to alter the pressure or pattern of airsupply to an infant for breathing. In accordance with the embodiment ofthe invention sche matically illustrated in FIG. 4, the magnitude ofnegative air pressure within the negative pressure chamber isautomatically altered in order to prevent such apnic spells.

Thus in FIG. 4 a negative pressure chamber or enclosure 38 (identicalfor example to the enclosure 11 shown in FIG. 1) has a vacuum inlet 39connected via a tube or pipe 41 to a vacuum pump 42. A valve 43 isconnected to the tube 41 and includes an inlet 44 to the atmosphere. Thevalve 43 has suitable control means for effecting the opening andclosing of the valve 43, which control means are illustrated by thesolenoid control apparatus 46, as shown in FIG. 4. In operation, whenthe valve 43 is open, the pump 42 through tube 41 is still producing anegative pressure within the chamber 38 in the same manner as describedbefore with reference to the apparatus illustrated in FIG. 1 as long theresistance of inlet 44 is higher than that of tube 41. When, however.the solenoid control 46 is ac mated to close the valve 43, air does notenter through the inlet 44 but passes only through the tube 41 to thepump 42, thus increasing the magnitude of negative pressure producedwithin the chamber 38 by the pump 42. The rate of an amount of negativepressure varia tion within the chamber 38 depends upon the size of thevalve 43, the inlet 44 and the tube 41, as well as the length of timethe valve 43 remains open or closed. In accordance with one embodimentof the invention, the solenoid control 46 is operated to close the valve43 in a cyclical fashion at a rate ranging from 2 or 3 per minute to 30or 40 openings per minute. The solenoid control 46 can hold the valve 43closed for a length of time which is also adjustable ranging from afraction of a second to several seconds. The length of time the valve 43must remain closed in order to produce the desired pressure variationsin the negative pressure within the chamber 38 depend upon thecharacteristics and capacity of the pump 42 and the leaks present in thebox.

With the arrangement of the invention shown in FIG. 4, continuousnegative pressure is still maintained about the thorax of the infant atall times; the magnitude of the negative pressure is varied. Further. inaccordance with the embodiment of the invention shown in FIG. 4, themaximum negative pressure to which the infant is subjected can beincreased since the maximum will not be continuously applied to theinfant. Thus, maximum negative pressures on the order of 25 centimetersof H 0 can be applied to the infants thorax with no deleterious effectsas long as the infant is not exposed to this maximum negative pressurefor too long a period. In a typical application of the embodiment of theinvention diagrammatically illustrated in FIG. 4 the negative pressurein the negative pressure chamber 38 might be varied at a rate of 20variations a minute from a minimum negative pressure of centimeters of H0 to a maximum negative pressure of 25 centimeters of H 0. Thisvariation is sufficient to prevent apnea while still continuouslymaintaining negative pressure about the thorax of an infant to maintainthe infants lungs in an inflated condition.

Thus, what has been described is a negative pressure chamber for use intreating infants having idiopathic Respiratory Distress Syndrome.Although the invention has been described with reference to particularpreferred embodiments, it should be obvious that modifications andadditions to the particular preferred embodiments disclosed are wellwithin the capability of those skilled in the art without departing fromthe true spirit and scope of the invention.

What is claimed is:

l. A continuous negative pressure chamber for treat ing infants havingIdiopathic Respiratory Distress Syndrome comprising an enclosure havinga top, a bottom, two spaced side walls and a front and a back spacedwith respect to each other and made of a material which is visuallytransparent and also transparent to X- rays, said front and back beingspaced from each other a distance of approximately centimeters, whichcorresponds to the distance between an infants neck and pelvic area,said front and back each having an opening aligned with each other andmounting an adjustable iris diaphragm for adjustably engaging the neckand pelvic area of an infant placed in the enclosure, a pressuremanometer mounted to said enclosure for providing an indication of theair pressure therein, a pressure relief valve mounted to said enclosurefor relieving the pressure in said enclosure if the pressure exceeds apredetermined limit, a vacuum inlet to said enclosure, and vacuum sourcemeans connected to said inlet for producing a continuous negativepressure in said enclosure, and heating means external to said enclosurefor heating air within and surrounding said enclosure so that air flowthrough said iris diaphrams does not produce a deleterious coolingeffect.

2. A continuous negative pressure chamber in accordance with claim 1wherein said enclosure includes a baffle placed inside said enclosureadjacent said vacuum inlet to prevent materials which might be containedwithin said enclosure from occluding said vacuum inlet.

3. A continuous negative pressure chamber in accordance with claim 1including a rod member mounted to each of said side walls and extendingparallel to said side walls and perpendicularly to said front and backand projecting predetermined distances beyond the front and back,whereby material my be wrapped around the projecting rod members toprovide support for the head and lower body portion of an infant placedin the chamber.

4. A continuous negative pressure chamber in accordance with claim 1wherein said vacuum source means is adjustable to provide a continuousnegative pressure within said enclosure within the range of 2-15centimeters of H 0.

5. A continuous negative pressure chamber in accordance with claim 1wherein said vacuum source means comprises a continuous vacuum pump andincluding a selectively operable valve connecting the vacuum pump tosaid vacuum inlet, and further including control means for cyclicallyopening and closing said valve for cyclically varying the magnitude ofcontinuous negative pressure maintained within said enclosure.

6. A continuous negative pressure chamber in accordance with claim 1wherein said heating means com prises an incubator surrounding saidenclosure.

1. A continuous negative pressure chamber for treating infants havingIdiopathic Respiratory Distress Syndrome comprising an enclosure havinga top, a bottom, two spaced side walls and a front and a back spacedwith respect to each other and made of a material which is visuallytransparent and also transparent to Xrays, said front and back beingspaced from each other a distance of approximately 15 centimeters, whichcorresponds to the distance between an infant''s neck and pelvic area,said front and back each having an opening aligned with each other andmounting an adjustable iris diaphragm for adjustably engaging the neckand pelvic area of an infant placed in the enclosure, a pressuremanometer mounted to said enclosure for providing an indication of theair pressure therein, a pressure relief valve mounted to said enclosurefor relieving the pressure in said enclosure if the pressure exceeds apredetermined limit, a vacuum inlet to said enclosure, and vacuum sourcemeans connected to said inlet for producing a continuous negativepressure in said enclosure, and heating means external to said enclosurefor heating air within and surrounding said enclosure so that air flowthrough said iris diaphrams does not produce a deleterious coolingeffect.
 2. A continuous negative pressure chamber in accordance withclaim 1 wherein said enclosure includes a baffle placed inside saidenclosure adjacent said vacuum inlet to prevent materials which might becontained within said enclosure from occluding said vacuum inlet.
 3. Acontinuous negative pressure chamber in accordance with claim 1including a rod member mounted to each of said side walls and extendingparallel to said side walls and perpendicularly to said front and backand projecting predetermined distances beyond the front and back,whereby material my be wrapped around the projecting rod members toprovide support for the head and lower body portion of an infant placedin the chamber.
 4. A continuous negative pressure chamber in accordancewith claim 1 wherein said vacuum source means is adjustable to provide acontinuous negative pressure within said enclosure within the range of2-15 centimeters of H2O.
 5. A continuous negative pressure chamber inaccordance with claim 1 wherein said vacuum source means comprises acontinuous vacuum pump and including a selectively operable valveconnecting the vacuum pump to said vacuum inlet, and further includingcontrol means for cyclically opening and closing said valve forcyclically varying the magnitude of continuous negative pressuremaintained within said enclosure.
 6. A continuous negative pressurechamber in accordance with claim 1 wherein said heating means comprisesan incubator surrounding said enclosure.